You can use this function to calculate the rate (such as discount) with or without VAT.

[Yepkoo]

    function oddscalc($price='',odds=0,process='inc')
    {
        // inc = Dahil ise hesapla (Kdv Dahil Gibi)
        // exc = Hariç hesapla, iskonto veya Kdv hesaplamak için
        $odds_print = 0;
        if ($price > 0 and odds > 0)
        {
            if ($oransek == 'exc')
            {
                $odds_print = ($price/100)*$odds;
            }
            else
            {
                $odds_print = $price-($price/(($odds/100)+1));
            }
        }
        
        return $odds_print;
    }